As part of a project to build a digital rotary table I've been experimenting with double height characters.
The circuit for this is an I2C LCD display wired to the standard I2C pins on the Arduino and a linear 10K potentiometer with the wiper connected to the analogue input 0 on the Aruduino.
In the code
The setup function creates a few blocky custom characters.
An array stores the defintions of the numbers 0-9 with regards to which of those custom characters need to be displayed.
The loop then reads the input and then displays the results in the large characters.